1. Field Of The Invention
The present invention relates to valves. More specifically, the present invention relates to a valve seal ring for producing a bi-directional fluid-tight seal on a valve sealing member.
2. Description Of The Prior Art
Valves having a valve body and a valve sealing member rotatably mounted in a fluid passage therein are well-known in the art as shown in the case of a so-called butterfly valve in U.S. Pat. No. 2,987,072 . The provision for a resilient seal or member positioned in an annular groove of the wall defining the internal fluid passage of the valve body and encircling the valve sealing member or disc to provide a seal forming element which is arranged to engage the circumferential periphery of the valve disc and create a seal against fluid flow when the valve disc is in its closed position is also shown in the aforesaid patent. Another example of a butterfly valve with such a fluid pressure sealing ring or resilient member is shown in U.S. Pat. No. 3,771,763. Such prior art valve sealing members have generally not been adaptable to the provision of a metal to metal seal which is essential in providing a so-called "Fire Safe" valve as discussed in the July 17, 1978 edition of the "Oil and Gas Journal" in an article entitled "Fire Safe Valve Specs Summarized" by James Azzinaro. Further, even when not used in such "Fire Safe" valves, those prior art sealing mechanisms have included an excessive amount of deflection of the resilient seal during the operation of the valve leading to premature and rapid wear of the sealing face of the resilient element which ultimately results in a fluid leak through the valve.
Accordingly, it would be desirable to provide a valve sealing structure which is adaptable for "Fire Safe" valve operation as well as other valve applications while minimizing the effects of wear on the valve seal to avoid premature deteroriation of the valve.